In laundry factories, cloth pieces with large areas such as bed sheets and cover fabrics are, after having been washed and dried, successively subjected to a spreading treatment with a spreading device, a press treatment (ironing) with a press device, and a folding treatment with a folding device. A predetermined number (such as 7 to 10 pieces) of the folded cloth pieces are packaged and delivered to customers.
Bed sheets used in hotels and guesthouses have various sizes depending on the bed sizes. Among them, a king size sheet in a spread state as shown in FIG. 4(A) generally has a length W of about 3 m in the longer length direction (right-to-left direction) and a length L1 of about 2 m in the shorter length direction (vertical direction). Some customers may also use a super king size sheet Y0 (as shown by the two dotted line in FIG. 4(A)) having right-to-left length W and vertical length L0 of each about 3 m. In the following description, the right-to-left direction and vertical direction of the cloth piece in the states shown in FIGS. 4(A) to 4(F) are occasionally referred to as transverse direction and longitudinal direction, respectively.
When such a king size sheet Y is folded into a small size, steps shown in (A) to (F) of FIG. 4 are generally carried out. Namely, the cloth piece Y after having been pressed is first folded into four (this is generally done by twice folding the cloth piece into two but is occasionally achieved by a single four-folding step) with a folding device along the three folding lines “a” (transverse lines) to obtain a folded cloth piece Y1, as shown in FIG. 4(B), having ¼ size of the original. This is next folded into two along the folding line “b” (longitudinal line) shown in FIG. 4(B) to obtain a folded cloth piece Y2, as shown in FIG. 4(C), having ⅛ size of the original. The resulting product is then folded into two along the folding line “c” shown in FIG. 4(C) to obtain a folded cloth piece Y3, as shown in FIG. 4(D), having 1/16 size of the original, and further folded into two along the folding line “d” shown in FIG. 4(D) to obtain a finally folded cloth piece Y4, as shown in FIG. 4(E), having 1/32 size of the original. Such finally folded cloth pieces Y4 are successively stacked on a stacking conveyor 44 as shown in FIG. 4(F). The stack Z of the folded cloth pieces consisting of, for example, 7 to 10 pieces is delivered to a succeeding step such as a packaging step.
In laundry factories, an apparatus for performing a series of cloth piece treatments as shown in FIG. 5 is used for folding a large area cloth piece such as a bed sheet, which has been washed and dried, into a predetermined small size. The cloth piece treating apparatus shown in FIG. 5 includes a spreading device 5 for spreading the large area cloth piece, which has been washed and dried, into a rectangular form, a press device 6 for pressing (ironing) the spread cloth piece Y, and a folding device 1 for folding the spread and pressed cloth piece Y into a predetermined small size. These devices are continuously arranged in series. Further, a stacking device 4 for stacking a predetermined number of folded cloth pieces is disposed continuously with the folding device 1. With such a cloth piece treating apparatus, washed and dried large area cloth pieces, when fed to the spreading device 5, are automatically subjected to each of the succeeding steps.
The spreading device 5 has a spreader 50 and a carry-out conveyor 51. The press device 6 has two, upstream-side and downstream-side rollers 62 and 62 (the press device having three rollers may also be used) disposed in a drying kiln 61. The folding device 1, which will be described in detail hereinafter, has a plurality of conveyors, including a receiving conveyor (first conveyor 11), disposed between left and right frames 10 and 10. A plurality of folders, including a first folder 21, are provided in predetermined locations of respective conveyors. The stacking device 4, which will be described in detail hereinafter, is disposed adjacent to an upper side portion of the folding device 1.
The apparatus for performing a series of the cloth piece treatments is operated such that the transfer speed of the cloth piece through the spreading device 5, press device 6 and folding device 1 is the same. However, the cloth piece transfer speed of the cloth piece treating apparatus may be adjustably changed within a range of 10 m/min to 60 m/min depending upon the kind of the cloth piece to be treated (for example, a cloth piece such as a cover fabric having two superposed layers, a cloth piece such as a bed sheet having a single layer, and a cloth piece having varying thickness). For example, in the case of a cloth piece such as a cover fabric having two superposed layers (or a cloth piece having a large thickness), the transfer speed of the cloth piece treating apparatus is made slow (for example, 10 m/min to 30 m/min), because it takes a long time to dry the cloth piece in the press device 6. In the case of a cloth piece such as a bed sheet having a single layer (a cloth piece having a small thickness, in particular), on the other hand, the transfer speed of the cloth piece treating apparatus is increased (for example, to 40 m/min to 60 m/min) because the drying time in the press device 6 is slow.
The present applicant already developed a folding device 1 as shown in FIG. 6 and FIG. 7 for use in an apparatus for performing a series of the cloth piece treatments. The folding device 1 shown in FIGS. 6 and 7 is disclosed in Patent Document 1 (FIGS. 6 and 5 of Japanese Unexamined Patent Publication No. 2007-105067).
The known folding device 1 shown in FIG. 6 and FIG. 7 is designed such that a sheet (spread cloth piece) Y0 having the expected maximum size (in which the width W and the length L0 in FIG. 4(A) and FIG. 5 are each about 3 m) can be suitably folded. The structure of the known device is described below.
The folding device 1 shown in FIG. 6 and FIG. 7 is provided with a total of nine conveyors including a first conveyor (receiving conveyor) 11 configured to receive a spread cloth piece Y (or Y0) from the press device 6, a second conveyor 12 provided adjacent to a terminal end portion of the first conveyor 11, a third conveyor 13 disposed for contact with a lower running section of the first conveyor 11, a fourth conveyor 14 disposed for contact with a lower running section of the third conveyor 13, a fifth conveyor 15 continuous with the fourth conveyor 14, a pair of a sixth conveyor 16 and a seventh conveyor 17 configured to grasp a cloth piece to be folded (cloth piece Y1 folded into four as shown in FIG. 4(B)) therebetween at an intermediate portion of the fifth conveyor 15, an eighth conveyor 18 disposed beneath the paired conveyors 16 and 17, and a ninth conveyor 19 disposed adjacent to an upper part of the eighth conveyor 18. The first to fifth conveyors 11 to 15 are supported between right and left frames 10 and 10.
The folding device 1 is also provided with a total of five folders including a first folder 21 (FIG. 6) provided between a terminal end portion of the first conveyor 11 and a starting end portion of the second conveyor 12 for folding the spread cloth piece Y (or Y0) into two, a second folder 22 (FIG. 6) provided between a terminal end portion of the third conveyor 13 and a starting end portion of the fourth conveyor 14 for folding the two-folded cloth piece into a cloth piece (Y1 of FIG. 4(B)) folded into four, a third folder 23 for folding the four-folded cloth Y1 conveyed on the fifth conveyor 15 into a cloth piece (Y2 of FIG. 4(C)) folded into eight, a fourth folder 24 provided between the eighth conveyor 18 and the ninth conveyor 19 for folding the eight-folded cloth Y2 into a cloth piece (Y3 of FIG. 4(D)) folded into sixteen, and a fifth folder 25 provided adjacent to a starting end portion of a delivery device 3 (a pair of grasping conveyors 31 and 32) for folding the sixteen-folded cloth Y3 into a cloth piece (Y4 of FIG. 4(E)) folded into thirty two. Each of the folders 21 to 25 is operated by extending and retracting a pushing plate with an air cylinder to fold a cloth piece into two at a half length portion in the transfer direction thereof.
The finally folded cloth piece (Y4 as shown in FIG. 4(E)) is transferred through the delivery device 3 to the stacking device 4. The delivery device 3 has a pair of grasping conveyors 31 and 32 configured to receive the finally folded cloth piece Y4, folded in the fifth folder 25, in starting end portions of the both conveyors 31 and 32. The folded cloth piece Y4 is then transferred to the stacking device 4 while being grasped between the two grasping conveyors 31 and 32.
The stacking device 4 has a pair of gate plates 41 and 41, an open/close device 42 for opening and closing the both gate plates, and a feed conveyor 43 operable to feed the folded cloth piece Y above the both gate plates 41 and 41. At a location just beneath and spaced from the both gate plates 41 and 41 is disposed a stacking conveyor 44 on which folded cloth pieces Y are successively stacked. The stacking conveyor 44 has a terminal end portion to which a withdrawing conveyor 45 is connected. A working table 46 is disposed at a terminal end portion of the withdrawing conveyor 45.
The second conveyor 12, which is configured to run in both directions by means of a motor 12a, is normally operated to run in the same direction (to the rear direction) as that of the first conveyor 11. When the half length position of the spread cloth piece Y (or Y0) which is conveyed on the first conveyor 11 arrives at the folding position of the first folder 21, however, a signal is generated from a controller 70 so that the second conveyor 12 runs in the opposite direction (front direction).
The cloth piece treating apparatus of FIG. 5 is adapted to treat spread cloth pieces with different sizes one by one. The first folder 21 of the folding device 1 is operable to precisely fold the cloth piece Y (or Y0), conveyed in a spread state, into two at the half length position thereof. In order to achieve this, it is necessary to measure the length (in the transfer direction) of each of the spread cloth pieces successively fed from the press device 6, before the half length position thereof arrives at the first folder 21 (first folding position Q) of the folding device 1.
The known apparatus uses a device 7 for measuring the length of the spread cloth piece as shown in FIG. 6, which has a cloth piece detector 71 (such as a photoelectric tube) for detecting a leading edge Ya and a trailing edge Yb of the spread cloth piece Y (or Y0) transferred from the press device 6. The length (L1 or L0) of the spread cloth piece Y (or Y0) in the transfer direction thereof is determined by the controller 70 from the period of time between the detection of the leading and trailing edges Ya and Yb of the spread cloth piece Y (or Y0) by the cloth piece detector 71 and the transfer speed of the cloth piece.
The cloth piece detector 71 generates an ON signal upon detecting the leading edge Ya of the spread cloth piece and generates an OFF signal upon detecting the trailing edge Yb of the spread cloth piece. The ON and OFF signals from the cloth piece detector 71 are inputted to controller 70. The controller 70 measures the time period between the detection of the leading and trailing edges Ya and Yb of the spread cloth piece by the cloth piece detector 71 (the time period over which the cloth piece detector 71 is in the ON state).
On the other hand, the transfer speed of the cloth piece in the folding device 1 is measured by, for example, inputting to the controller 70 the driving speed of a motor 72 that drives the first conveyor 11.
Thus, the length of the spread cloth piece Y (or Y0) in the transfer direction thereof is computed in an operating part of the controller 70 from the time period between the detection of the leading and trailing edges Ya and Yb of the spread cloth piece by the cloth piece detector 71 (the time period over which the cloth piece detector 71 is in the ON state) and the transfer speed of the cloth piece (driving speed of the motor 72) in that period. For example, when the transfer speed of the cloth piece is 60 m/min (maximum speed) and the time period over which the cloth piece detector 71 is in the ON state is 2 seconds, then the length of the spread cloth piece in the transfer direction thereof is calculated to be 2 m (length L1 in FIG. 4(A) and FIG. 5). Similarly, when the transfer speed of the cloth piece is 60 m/min and the time period over which the cloth piece detector 71 is in the ON state is 3 seconds, then the length of the spread cloth piece in the transfer direction thereof is calculated to be 3 m (length L0 in FIG. 4(A) and FIG. 5). When the period of time required for the half length position of the spread cloth piece to arrive at the folding position Q of the first folder 21 has elapsed after the length of the spread cloth piece in its transfer direction was measured, the first folder 21 receives a signal from the controller 70 and starts operating. At the same time, the second conveyor 12 starts running in the opposite direction so that the spread cloth piece is folded into two at the half length portion.
In order to precisely fold the cloth piece Y (or Y0) into two at the half length position thereof by first folder 21 of the folding device 1, it is necessary to previously measure the length L1 (or L0) in the transfer direction of the spread cloth piece Y (or Y0). Since the length of the cloth piece is determined by calculation from the time period between the detection of the leading and trailing edges Ya and Yb of the spread cloth piece by the cloth piece detector 71, it is essential that, at a time point at which the cloth piece detector 71 has detected the trailing edge Yb, the half length position of the spread cloth piece (the position at which the cloth piece is to be folded into two) has not yet arrived at the folding position Q of the first folder 21. For example, when the spread cloth piece of a super king size has a length L0 of 3 m, it is necessary that the cloth piece detection position by the cloth piece detector 71 (namely, position P at which the detector is disposed) should be spaced apart a distance R, which is greater than the half length (1.5 m by simple calculation) of the spread cloth piece Y0 (with a length L0 of 3 m), from the first folding position Q toward the front side. In actual, the spacing distance R is set at about 70% (about 2.1 m) of the expected maximum length (3 m) of the cloth piece Y0 in view of possible delays in response of the cloth piece detector 71, in computation and output of the controller 70 and in response of the first folder 21. As long as the spacing distance R is set at 2.1 m, even when the cloth piece with the maximum length (3 m) is treated with the highest speed (60 m/min), a time of 0.6 second (time required for displacing a distance of 0.6 m (2.1 m-1.5 m) at a speed of 60 m/min) is available from the time point at which the terminal edge Yb is detected by the cloth detector 71 to the time point at which the half length position (position at which the cloth piece is to be folded into two) of the spread cloth piece arrives at the folding position Q of the first folder 21. Therefore, even when the apparatus is operated under the most severe conditions (the cloth piece with the maximum length of 3 m is treated at the highest transfer speed of 60 m/min), it is possible to precisely fold the cloth piece into two after the measurement of the length thereof (delays in response of respective devices may be absorbed). Stated otherwise, with the cloth piece treating apparatus of the above-described type, it is necessary that the spacing distance R between the position P at which the cloth piece detector 71 is disposed and the folding position Q by the first folder 21 of the folding device 1 should be at least slightly greater than 2 m (2.1 m in the case of the above case) in order to match with the case in which the cloth piece with the longest length of 3 m is treated at the highest transfer speed of 60 m/min.
In the known cloth piece treating apparatus shown in FIG. 5 to FIG. 7, the cloth piece detector 71 of the cloth piece length measuring device 7 is disposed in the folding device 1 (above the first conveyor 11). In this case, because the spacing distance R between the detector position P and the first folding position Q is about 2.1 m as described above, it is unavoidable to locate the detector position P at a position significantly forward (front side) of the folding device 1 even when the first folder 21 is disposed at a position significantly rear side of the folding device 1 as seen in FIG. 5 and FIG. 6.
Thus, in the known cloth piece treating apparatus shown in FIG. 5 and FIG. 6, since the cloth piece detector 71 is disposed at a position above the first conveyor 11 of the folding device 1, it is necessary that the length E1 (FIG. 5) of the first conveyor 11 should exceed 2.1 m (E1=about 2.2 m). As a consequence, the starting end portion 11a of the first conveyor 11 should extend significantly forward (front side). In particular, in the embodiment shown in FIG. 5, the starting end portion 11a of the first conveyor 11 extends forward (toward front side) to a position a length of F (F=about 70 cm) from a front edge 10a of the frame 10. Thus, in the cloth piece treating apparatus shown in FIG. 5 and FIG. 6, the front to rear length C1 of the folding device 1 (including the stacking device 4, carry-out conveyor 45 and working table 46 which are disposed continuously with the folding device 1) is as long as about 3.7 m.    Patent Document 1: Japanese Unexamined Patent Publication No. 2007-105067 (FIG. 5 and FIG. 6)